Amplified impedimetric aptasensor based on gold nanoparticles covalently bound graphene sheet for the picomolar detection of ochratoxin A
Amplified impedimetric aptasensor based on gold nanoparticles covalently bound graphene sheet for the picomolar detection of ochratoxin A
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基于元素螯合标记和毛细管电泳电感耦合等离子体质谱的溶菌酶超灵敏定量
DOI：
10.1016/j.aca.2013.11.003
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发表时间：
2014-01-02
影响因子：
6.2
通讯作者：
Wang, Kun
中科院分区：
文献类型：
--
作者：
Jiang, Ling;Qian, Jing;Wang, Kun
开发了一种具有皮摩尔灵敏度的赭曲霉毒素 A (OTA) 放大电化学阻抗适体传感器。制造金纳米颗粒共价结合还原氧化石墨烯 (AuNPs-rGO) 的简便方法是在石墨烯片上产生大量分散良好的 AuNP，并具有巨大的 DNA 结合位点，因为单个 rGO 片和每个 AuNP 可以负载数百条 DNA 链。制作了夹心模型的适体传感器，其中将硫醇化捕获DNA固定在金电极上以捕获适体，然后将传感界面与所需浓度的OTA一起孵育，然后将AuNPs-rGO功能化的报告DNA与残留的适体杂交。通过利用 AuNPs-rGO 作为出色的信号放大平台，适配体和报告 DNA 之间的单个杂交事件被转化为超过 10(7) 个氧化还原事件，导致电荷转移电阻 (R-ct) 与游离适配体修饰电极相比大幅增加了 7 个数量级。这种设计的适体传感器在1 pg mL(-1)-50 ng mL(-1)的宽范围内表现出R-ct对OTA浓度增加的响应减弱，并且可以检测极低的OTA浓度，即0.3 pg mL(-1)或0.74 pM，远低于大多数其他现有的阻抗适体传感器。这里介绍的信号放大平台将为采用直接阻抗法的基于适体的检测提供一个有前景的模型。 (C) 2013 Elsevier B.V. 保留所有权利。
An amplified electrochemical impedimetric aptasensor for ochratoxin A (OTA) was developed with picomolar sensitivity. A facile route to fabricate gold nanoparticles covalently bound reduced graphene oxide (AuNPs-rGO) resulted in a large number of well-dispersed AuNPs on graphene sheets with tremendous binding sites for DNA, since the single rGO sheet and each AuNP can be loaded with hundreds of DNA strands. An aptasensor with sandwich model was fabricated which involved thiolated capture DNA immobilized on a gold electrode to capture the aptamer, then the sensing interface was incubated with OTA at a desired concentration, followed by AuNPs-rGO functionalized reporter DNA hybridized with the residual aptamers. By exploiting the AuNPs-rGO as an excellent signal amplified platform, a single hybridization event between aptamer and reporter DNA was translated into more than 10(7) redox events, leading to a substantial increase in charge-transfer resistance (R-ct) by 7 similar to orders of magnitude compared with that of the free aptamer modified electrode. Such designed aptasensor showed a decreased response of R-ct to the increase of OTA concentrations over a wide range of 1 pg mL(-1)-50 ng mL(-1) and could detect extremely low OTA concentration, namely, 0.3 pg mL(-1) or 0.74 pM, which was much lower than that of most other existed impedimetric aptasensors. The signal amplification platform presented here would provide a promising model for the aptamer-based detection with a direct impedimetric method. (C) 2013 Elsevier B.V. All rights reserved.